My research interests are aimed at understanding costimulation and transcriptional control of T cell differentiation. We are studying the costimulatory molecules CD70 and CD27 in CD8 T cell responses using CD27 KO and CD70 Tg mice. Currently, we are investigating how costimulation through CD70 and CD27 maintains clonal diversity in CD8 T cell responses. We are also investigating the role of an undescribed transcription factor that we picked up in a screen of human CD8 T cells to be upregulated in the effector compartment. We named this transcription factor Hobit and found that expression was limited to cytotoxic cells (NK cells, effector CD8 T cells and cytotoxic CD4 T cells). In mice expression was much more restricted and only found in NKT cells. We are pursuing the role of Hobit in human studies and in mouse studies using newly developed Hobit KO mice.